Questions To what extent do changes in management (abandonment and fertilization) affect plant functional and taxonomic diversity in wet meadow communities? To what extent do the changes in functional and taxonomic diversity depend on site productivity? Location Železné hory Mts., Czech Republic. Methods Experimental plots were established on 21 wet meadows differing in productivity and species composition. In each meadow, in 2007, four 1 × 1 m plots were established, representing a full factorial design with abandonment and fertilization as the factors. In each plot, the number of species present was recorded in 100 subplots (0.1 × 0.1 m) in the years 2007, 2009 and 2011. Different indicators of functional diversity (functional richness, functional evenness, and Rao′s quadratic entropy) were calculated using five functional traits (SLA, LDMC, seed mass, plant height and clonality). Both abundance‐weighted and non‐weighted diversity indices were calculated. Randomization tests (conducted with PERMANOVA) were used to assess the effect of site productivity and management on both α‐ and β‐diversity components. Results Meadows along the productivity gradient differed in functional and taxonomic diversity. Both abandonment and fertilization decreased taxonomic diversity. Whereas fertilization decreased functional richness and Rao′s quadratic entropy, abandonment decreased functional evenness. The changes in both taxonomic and functional diversity caused by abandonment and fertilization occurred faster in more productive meadows. Conclusions The increased dominance of tall species with abandonment and fertilization, followed by the loss of species and the decrease in various indicators of functional diversity, suggest that increased competition for light resulted in increased trait convergence among co‐existing species. In addition, many processes occurring after abandonment and fertilization depend on meadow productivity. Results suggest that abundance‐ and non‐abundance‐weighted diversity indices give complementary insights on community structure. These results imply that changes are needed in current meadow management and conservation.

Semi‐natural meadows host a great number of species coexisting at fine spatial scales. Different assembly mechanisms, related to differences in functional traits between species, can influence such coexistence. Coexisting species could be either functionally dissimilar to occupy different niches (‘divergence’) or functionally similar due to exclusion of species with traits less adapted to the prevailing abiotic and biotic conditions (‘convergence’). Various theories differently predict how trait convergence and divergence should differ due to disturbance, along productivity gradients, and across different functional traits. We tested such theories in 21 wet meadows of different productivity in central Europe. In each meadow, four 1 × 1 m plots were established in which disturbance by mowing was combined with fertilization. Species presence was recorded in 100 quadrats 10 × 10 cm in size within the plots over five years. Convergence and divergence were assessed at very fine spatial scales (10 × 10 cm) to focus on the processes driven by the interactions for similar resources. Convergence emerged as the dominant pattern for all traits and across all years. It was particularly strong in the least productive conditions while divergence emerged in some of the most productive meadows. Mowing increased convergence in meadows with low productivity, but increased divergence in productive meadows. Fertilization generally increased convergence, with this increase being more pronounced in mown plots. Convergence in unproductive conditions could be caused by either higher fitness of stress‐tolerant species (more abundant in the species pool of these sites) or by functionally similar species sharing similar patches within fine‐scale heterogeneous plots. This outcome also suggests abiotic filters can have an important role at fine scales, where plant‐ecological theory usually predicts the prevalence of biotic processes.

Summary Dominance of native or alien competitive plants causes competitive exclusion of subordinate species and represents a major mechanism reducing biodiversity following land‐use changes. The successful competitive strategies may, however, be interfered with by parasitic plants, which withdraw resources from other plants' vasculature. Parasitism may strongly reduce the growth of the dominants, which may facilitate regeneration of other species and consequently trigger restoration of natural communities of high diversity. Here, we aim to provide robust empirical evidence demonstrating this restoration potential of parasitic plants. We present a case study testing suppressive effects of hemiparasitic Rhinanthus alectorolophus on competitive grass Calamagrostis epigejos. In recent decades, C. epigejos has invaded many high‐nature‐value semi‐natural grasslands of Central Europe, which is one of the prominent factors causing their biodiversity decline. We conducted three manipulative field experiments testing the effect of sowing of R. alectorolophus in different vegetation types infested by C. epigejos. Rhinanthus sowing was compared to different mowing treatments recommended as the ‘best practice’ management at respective sites. Rhinanthus alectorolophus established itself in most C. epigejos‐dominated plots where sown. Calamagrostis epigejos was virtually exterminated in 2 years in two of the experiments (dry meadow and industrial area). In the wet‐meadow experiment, the suppressive effect was variable as a result of uneven establishment success of Rhinanthus. In this experiment increased mowing intensity had an additional suppressive effect on C. epigejos. Rhinanthus also increased regeneration potential of other species by a temporary reduction of vegetation density. Restoration of target vegetation composition was, however, dependent on community context. Synthesis and applications. We demonstrated that hemiparasitic Rhinanthus alectorolophus is an accessible and efficient tool for targeted biological control of Calamagrostis epigejos, with a great potential to restore infested grassland vegetation. The strong effect of Rhinanthus is caused by interference with the underground storage and clonal growth strategy of Calamagrostis epigejos, which are both traits that underlie its competitive ability. The potential of native parasitic plants should be considered in restoration management of sites infested by competitive dominants, either alien or native.

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Abbreviations CWM = community-weighted mean; SLA = specific leaf area; LDMC = leaf dry matter content; LMM = linear mixed effect models. NomenclatureKub at et al. (2002) for plants; Moravec (1995) for plant communities Abstract Questions: Wet meadows have traditionally been managed at low intensity, promoting the co-existence of a variety of plant species. The remaining fragments of these meadows are now being degraded by either mowing abandonment or by agricultural intensification, such as increased fertilization. We tested the theoretical expectation that certain functional traits can explain vegetation changes along gradients of productivity and soil moisture in response to these land-use changes. Location:Zelezn e hory Mts., Czech Republic, Central Europe. Methods:We set up a long-term experiment where we applied a full factorial design of fertilization and abandonment to 17 traditionally mown wet meadows covering a broad range of productivity and soil moisture conditions found within the region. Plant functional traits that cover different aspects of plant ecological strategies -plant height, specific leaf area (SLA), leaf dry matter content (LDMC), seed mass and clonality -were used to explain both species and whole community response to land-use change. We employed linear mixed effect models to test for the consistency of functional changes across different productivity and soil moisture conditions. Results: We found that the functional response of species and whole communities to land-use change was consistent across meadows differing substantially in their productivity and soil moisture. Specifically, irrespective of the local conditions, both fertilization and abandonment selected for tall species within communities, highlighting the effect of increased competition for light. Traits related to a more exploitative strategy in species (higher SLA, more prominent clonal growth and smaller seeds) were consistently favoured with increased fertilization. Conclusions:We show that within a given region with a common land-use history, certain functional traits consistently explain and can help to predict changes in plant communities caused by land-use change, irrespective of different productivity and soil moisture conditions. Our results demonstrate a simple way to use functional traits in applied nature conservation. We hope this will encourage practitioners to use functional traits to complement existing knowledge on composition and productivity of considered habitats to enhance the planning of management practices. We encourage practitioners to build regional trait databases to actively use trait information for the purpose of habitat management.

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Questions: Theory suggests that while plant diversity of grasslands decreases in response to increased competition for light, many plant species persist below-ground even in the temporary absence of shoots. Thus, we hypothesized that below-ground, diversity is less affected by increased competition during land-use change compared to above-ground. Location: Species-rich, oligotrophic grasslands in the Železné hory Mts, eastern Bohemia, Czech Republic. Methods: We quantified above-and below-ground plant richness (roots and rhizomes, seed and bud bank) in grasslands subjected to seven years of experimental abandonment and fertilization. We used conventional species identification to measure richness above-ground and 454 sequencing of the chloroplast trnL (UAA) gene to measure richness of roots and rhizomes; additionally, we used the shoot emergence method to measure soil seed and bud bank richness. Results: While above-ground richness decreased with abandonment and fertilization, below-ground richness remained less affected or even increased compared to the control (traditional mowing). Overall, compared to above-ground the proportion of plant species found only below-ground as roots and rhizomes increased, particularly in the abandonment with fertilization treatment. Conclusions: Below-ground plant diversity could potentially buffer against biodiversity losses during short-term land-use change. Our findings highlight that measuring the complete plant species diversity improves our understanding of processes that underlie plant diversity and coexistence and refine predictions of vegetation responses to biodiversity threats.